Bore hole perforating apparatus



April 13, 1965 H. D. OWEN 3,177,808

BORE HOLE PERFORATING APPARATUS Filed March 13, 1961 2 Sheets-Sheet 1FIG. I

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INVENTOR. HARROLD D. OWEN f 4%f/1 L ATTORNEY April 13, 1965 H. D. OWEN3,177,808

BORE HOLE PERFORATING APPARATUS Filed March 15, 1961 2 Sheets-Sheet 2INVENT-OR. HARROLD D. OWEN ATTORNEY United States Patent 3,177,863 BQREHGLE PERFGRATIN G APPARATUS Harrold 1). Owen, 4390 Lanark, Fort Worth,Tex. Filed Mar. 13, 1961, Ser. No. 95,375 6 Claims. at. 102-20 Myinvention relates to bore hole perforating apparatus, and moreparticularly to perforating apparatus of the type utilizing shapedcharges. The invention is especially concerned with the structure andarrangement of shaped charge units and carrying assemblies.

In oil well production, after a well is drilled and cased, it isperforated at the expected zone or zones of production in order to allowoil to flow from the earth formation through the casing cement andeasing wall into the well. Each individual perforation is made by thefiring of a single shaped charge unit. Since it is desirable to have anumber of perforations in each producing zone, the shaped charge unitsare always arranged in groups on some sort of charge carrier device.Although numerous types and arrangements of shaped charge units andcarrier devices have been devised in the prior art of which I am aware,all of them are subject to some shortcomings and fall short of theideal.

For convenience herein, the phrase shaped charge unit may be defined asa single and complete shaped charge, including the charge body orhousing, the cap or body front and closure, the explosive material orcharge, and the liner. The phrase shaped charge carrier may be definedas a single unitary structure adapted for the mounting or carrying of aplurality of shaped charge units. The phrase shaped charge gun may bedefined as a single shaped charge carrier with a plurality of shapedcharge units mounted on it. The phrase shaped charge gun assembly may bedefined as simply a plurality of shaped charge guns linked together. Forfurther convenience, the above defined phrases may at times herein bereferred to as charge unit, carrier, gun, and gun assembly,respectively.

It takes a combination of several important attributes to make a shapedcharge gun assembly which will approach the ideal. A good gun assemblyshould, when fired, produce as little debris as possible, since debrisresulting from firing a poor gun assembly can clog the well and, in somecases, seriously interfere with various production operations. Sometypes of gun assemblies will leave so-called carrots in the earthformation perforation. These carrots are the remains of the charge unitliner which is forced into the perforation by the action of the shapedcharge. The carrots can interfere with the free flow of oil through theearth formation perforation. The best way to prevent formation ofcarrots is to have the charge units exposed to the well fluid. A goodgun assembly should not have carrot formation tendencies. When a gunassembly is fired to perforate a well production zone, it is mostdesirable to have some way of determining which charge units fired andwhich did not. A god gun assembly should provide thisinformation in apositive form. In addition, a good gun assembly should be simple, lightweight, versatile, economical to manufacture, and easy to load andassemble. A good gun assembly should also be capable of readilynegotiating the well bore, pipe, casing, or tubing, without gettingstuck.

The' broad object of my invention, accordingly, is to provide animproved shaped charge gun and gun assembly. Stated more specifically,the object of my invention is to provide a shaped charge gun assemblywhich shall have all of the attributes of a good gun assembly asoutlined above to the maximum possible degree.

In accordance with my invention, the shaped charge carrier may be simplya straight metal strip or strip body "ice having a plurality of openingscentered at spaced intervals along its length for receiving chargeunits, and provided at its ends with linking joint elements. In one formof the invention, the strip body may be a straight shallow chan nelmember having sufficient structural strength to prevent disintegrationand having sufiicient rigidity to assure retention of desired chargeunit orientation. The channel member will have an opening centered inthe channel for each shaped charge unit, with the openings being spacedso as to give the desired perforation spacing. Each charge unitpreferably will have a body portion and a cap portion. Each charge capportion is arranged to protrude through a carrier opening and means areprovided to lock the cap onto the carrier. When the charge units isdetonated, it perforates the cap, and since the cap remains locked ontothe carrier, and since the carrier is retrieved, there is a positiveindication as to whether or not each charge unit fired. The charge capwill'be made of nonfrangible material, while the charge body willpreferably be made of frangible material. The charge cap is prefer-ablymetal, for example, almuinum. The charge body may be either frangiblemetal or other frangible material such as plastic or glass. As manycharge guns as desired may be linked together to make a charge gunassembly. In one form of the invention, the charge gun assembly is madeup of charge guns all facing the same direction. If desired, some of thecharge guns can be fixed in one direction, and others in the oppositedirection. In still another form of the invention, one or more chargeguns may be arranged to fire in a first direction, and others arrangedto fire in directions displaced and 270 from the first direction. Ineach case, the charge gun linkages are of a type allowing swiveling orpivoting action about two transverse axes 90 apart, but allowing notwist action about the gun assembly longitudinal axis, since a twistaction would upset the charge orientation. The specific arrangements foraccomplishing the above constitute some of the features of my inventionand will be hereinafter fully described.

For a more complete understanding of my invention and for furtherobjects and advantages thereof, reference may now be had to thefollowing description taken in accordance with the accompanyingdrawings, forming a part of this application, in which:

FIGURE 1 is a schematic rear elevational view of a shaped charge gunassembly in -accordance with a preferred embodiment of my invention;

FIGURES 2, 3, and 4, respectively, are schematic fragmentary rear, sideand front elevational views showing details of a portion of a shapedcharge gun and a linkage arrangement;

FIGURE 5 is a schematic fragmentary side elevational view, partly insection, showing a shaped charge unit mounted on a carrier;

FIGURE 6 is a schematic perspective view showing details of the linkageof FIGURES 1-4;

FIGURE 7 is a schematic side elevational view of the male linkageelement of FIGURE 6;

FIGURES 8 and 9, respectively, are schematic frag mentary front and rearelevational views showing charge unit caps and carrier after a gun hasbeen fired and retrieved;

FIGURE 10 is a schematic elevational view showing a shaped charge gunassembly in accordance with another embodiment of my invention; and

FIGURE 11 is a schematic fragmentary perspective view showing details ofthe linkage of the type used in the gun assembly of FIGURE 10. i

In FIGURE 1 there is shown a shaped charge gun assembly 11 made up of aplurality of shaped charge guns 13. Adjacent chargeguns 13 are heldtogether by a linkage 15. The upper linkage of the assembly 11 may befixed to conventional cable suspension and detonating apparatus (notshown). Conventional prima cord 17 is threaded through each charge unitopening 19 provided for that purpose. Each charge unit carrier is simplya straight shallow channel member 21 having a plurality of spacedopenings 23 centered on the channel web along its length. The channelmaterial has suflicient structural strength to provide rigidity so as tomaintain the charges in predetermined orientation relation and toprevent disintegration and undue deformation upon firing, so that theassembly may be retrieved intact except for the charge unit body 25,thecharge 27, liner 29 and prima cord 17. The channel width ispreferably just greater than the charge body diameter, and the channelsides 31 are just high enough to provide requisite rigidity. Channelstock made of steel having thickness has been found satisfactory for thecarrier. Each carrier 21 may have any desired length, but is preferablymade sufiiciently short to enable negotiation of the gun assemblythrough the well pipe, taking into account the pipe crooks and bendsthat may be encountered. A typical carrier length may be approximatelyinches, allowing for the mounting of four charge units on 6 inchcenters, plus additional length necessary to accommodate the linkageelements. The channel openings 23 are preferably circular with adiameter sufiiciently larger than that of the protruding portion of thecap to allow for easy assembly with loose manufacturing tolerances.

As best shown by FIGURE 5, each shaped charge unit 26 has a body orhousing 25, a shaped charge 27, a liner 29, and a cap 33. The chargebody has a cylindrical portion 35 closed at one end by an integralconical portion 37. The cylindrical portion 35 has a reduced outerdiameter in the region of the body open end. The shaped charge 27 isformed within the body interior with a conical cavity in its front face,the cavity axis being common with the body cylindrical portion axis. Thecharge liner 29 is in the shape of a cone designed to conform to thecharge face. The charge body 25 is provided with an integral cylindricalprojection centered on the charge body conical portion 37 and having atransverse cylindrical opening 19 adapted for receiving prima cord 17.The charge cap 33 has a cylindrical portion 39 merging with afrusto-conical portion 41 which in turn terminates in a cylindricalprojection 43 which is threaded at its outer end portion. The innersurface of the short cylindrical portion 39 of the cap is sizedto matewith the reduced diameter portion 45 of the body 25. A sealing gasket 47is provided for sealing the cap 33 onto the body 25. The cap interiouisprovided with a cylindrical cavity 49 so as to make the cap end wall 51easy to perforate. To assemble a charge unit 26 onto a carrier 21, it isonly necessary to insert the cap threaded cylindrical, projection 43through the charge carrier opening 23, and thread a lock nut 53 onto theprojection 43, pulling the cap 33 snugly and rigidly against the Web ofthe carrier 21.

After the charge units have been assembled onto the carriers, aplurality of charge guns may be linked together to make up a shapedcharge gun assembly. One form of linkage which has been found verysatisfactory is that shown by FIGURES 2, 3 4 and 6. As shown in FIG- URE6, the linkage 15 is made up of a male member 55 and a female member 57.Both themale and female linkagermembers 55, 57 have shank portions 59 inthe form of a rectangular plates of width substantially equal to that ofthe carrier channel web. The male portion 55 has a head ortongue 61 intheform of awafer, the faces of which are parallel to the shank faces. Aneck 63 is integral at one end with the head 61 and at the other'endwith the juncture of the head and shank forming a should der 69. Thefemale linkage head'portion 67 has a central circular opening 71 whichmerges with a channel 73 opening which extends from the circular openingto the head outer face. In assembly, the head or tongue 61 of the malemember makes a loose fit within the circular opening 71 of the femalemember head, and the male member neck 63 extends within the channelopening 73 of the female member head with side clearance. The malemember head 61 has a transverse slot opening 75 centered between itsfaces. In assembly, this slot opening receives a pin 77 which is carriedby the female portion head 67 and which extends. diametrally of thecircular opening 71 and transversely of the linkage memben 5 7. The pindiameter is made substantially equal to the depth of the slot 75, butthe slot width is much greater than its depth. Each linkage member shank59 is provided with a threaded opening 79 at its approximate center. 'Inassembly, each shank 59 is clamped within the channel at the end of arespective carrier 21 by a respective stud 81. The fit of the shank 59in the channel and the shoulder 65, 69 with the end of the channel holdseach linkage member 55, 57 rigid relative to its respective carrier 21.Thus, when assembled, the linkage of FIGURE 6 allows limited freedom ofmovement about the axis .of the pin 77 (see FIGURE 3) and limitedsideways movement about a transverse axis displaced 90 from the pin axis(see FIGURE 2), but there can be no twisting movement about the linkagelongitudinal axis. This allows shaped charge gun assembly to negotiatecrooks and bends in the well pipe while maintaining desired charge unitorientation.

The shaped charge gun assembly shown by FIGURE 10 may be identical withthat of FIGURE 1, except for the linkage members. For simplicity,corresponding parts in the drawings have been given the same referencenumerals. Although the carriers 21 of FIGURE 10 show only two chargeunits 26 each, they may have more if desired. The linkage members 83 ofFIGURE 10 have the same purpose as those of FIGURE 1, namely, to allowrelative pivoting movement of adjacent carriers about two transverseaxes, but no twisting movement about the gun assembly longitudinal axis.In addition, however, the linkages of FIGURE 10 are are designed topermit the guns to be oriented 90 apart. Details of the linkages ofFIGURE 10 are shown by FIGURE 11. As seen from FIGURE 11, the linkage 83is simply a single short angle member having a first side 85 displacedfrom a second side 87. The first side 85 is pivoted near its end portiontothe end portion of one carrier 21 by means of a bolt and nut, whilethe second side 87 is also pivoted near its end portion to an adjacentcarrier by means of a bolt and nut 91. The width of each side 85, 87 ofthe linkage member 83 is made less than that of the carrier channel webto permit limited motion about the respective pivot. axis. Each side 85,87 of the linkage member 83 is inwardly tapered to the other side at theend portion away from the side pivot end. Thus, the links age 83 allowsrelative movement of adjacent carriers 21 about two transverse axes, butdoes not permit any twisting motion about the gun assembly longitudinalaxis. The linkage 83 also .acts to orient adjacent carriers 90 apart.

;It willbe apparent from the foregoing that I have provided shapedcharge gun and. gun assemblies which are essentially free of debris,since the entire assembly is retrieved except for the charge unit bodyportion and the prima cord. When the charge unit body is made offrangible material, it will break up into very. smalljpieces upon chargedetonation. Also, the gun assemblies are entirely open so that debriscan fall free without any danger of clogging the gun assembly. Becausethe gun assemblies of my invention keep the charge units exposed to thewell fluid, the'tendency toward carrot formation is minimized. Since thecharges all perforate the caps, and the caps remain fixed to the carrierwhich is retrieved, there is provided a positive indication in each caseas to whether or not a particular charge unit performed its intendedperforating function. Further, the gun assemblies of my invention arecapable of negotiating crooks and bends in the Well pipe whilemaintaining desired charge orientation. In addition, the gun assembliesof my invention are simple, light in Weight, versatile, economical tomanufacture, and easy to load and assemble.

The foregoing disclosure and the showings made in the drawings aremerely illustrative of the principals of my invention, and are not to beinterpreted in a limiting sense.

I claim:

1. A shaped charge gun for perforating in bore holes comprising aplurality of shaped charge units each having a front end closureincluding a threaded cylindrical front end portion merging with ashoulder, a carrier in the form of a rigid elongated member having aplurality of spaced openings therein, with each charge unit beingdisposed on said carrier With said front end closure protruding througha respective opening, and a nut engaging each said threaded portion andbearing on said member for fixing said respective charge unit to saidmember, with said charge unit shoulder bearing on said member on theside opposite said nut.

2. A shaped charge gun for perforating in bore holes comprising aplurality of shaped charge units each having a non-frangible front endportion arranged to be perforated by firing of said unit, an open facedcarrier member having a plurality of spaced openings therein, and meansfixing each said charge at said front end portion to said member at arespective opening thereof.

3. A shaped charge gun for perforating in bore holes comprising an opencarrier member having a plurality of openings therein, a plurality ofshaped charge units each having a body and a non-frangible cap arrangedto be perforated by firing of said unit, and means fixing each said capto said carrier at a respective opening thereof for sole support of saidunit by said cap and said means.

4. A shaped charge gun for perforating in bore holes comprising aplurality of shaped charge units each having a body portion and anon-frangible end closure cap sealably mounted thereon, an open carriermember having a plurality of spaced openings therein, a threadedprotrusion on the end portion of each said cap remote from said body andextending through a respective carrier opening, and a nut engaging saidthreaded protrusion and locking said cap to said carrier.

5. A shaped charge gun assembly comprising a plurality of charge unitcarriers in the form of rigid elon- 6 gated members; a linkage joiningeach two adjacent carriers; each linkage including a male and a femalemember each having a shank portion; means securing said shank portionsto the end portions of respective said carriers; a neck portion integralwith the shank of said male member and integral with and terminating inan enlarged tongue portion having an arcute peripheral surface; a headportion integral with the shank of said female member and providing anopening having a first portion for receiving said male member tongueportion and a second portion for receiving said male member neckportion;

said first and second opening portions having surfaces contoured to mateloosely With corresponding tongue and neck portions so as to permitrelative movement of said adjacent carriers about a respective firstaxis perpendicular to the longitudinal axis of a respective carrier,With said movement being guided by the loosely mated tongue and firstopening portion and limited by cooperation of said second openingportion with said neck; and means pivotally securing said male member tosaid female member for relative pivoting movement about a second axisperpendicular to said respective first axis, said last mentioned meansincluding a slot in said tongue and a pivot shaft extending through saidslot, with said slot being sized to permit said relative pivotingmovement about said respective first axis.

6. A shaped charge gun for perforating in bore holes comprising aplurality of shaped charge units each having a body and a non-frangiblecap sealably mounted to said body and to be perforated upon firing ofsaid unit, an open carrier member having a plurality of spaced openingsthereon, and means fixing each said cap onto said carrier at arespective said opening for sole support of said unit by said cap andsaid means.

References Cited by the Examiner UNITED STATES PATENTS 491,469 2/93Carver 287 2,266,345 12/ 41 Turechek 89-1 2,756,677 7/56 McCullough10220 2,799,224 7/57 Long 102-20 2,981,185 4/61 Caldwell 102-20 FOREIGNPATENTS 184,886 3/56 Austria.

BENJAMIN A. BORCHELT, Primary Examiner.

SAMUEL FEINBERG, SAMUEL BOYD, Examiners.

1. A SHAPED CHARGE GUN FOR PERFORATING IN BORE HOLES COMPRISING APLURALITY OF SHAPED CHARGE UNITS EACH HAVING A FRONT END CLOSUREINCLUDING A THREADED CYLINDRICAL FRONT END PORTION MERGING WITH ASHOULDER, A CARRIER IN THE FORM OF A RIGID ELONGATED MEMBER HAVING APLURALITY OF SPACED OPENINGS THERIN, WITH EACH CHARGE UNIT BEINGDISPOSED ON SAID CARRIER WITH SAID FRONT END CLOSURE PROTRUDING THROUGHA RESPECTIVE OPENING, AND A NUT ENGAGING EACH SAID THREADED PORTION ANDBEARING ON SAID MEMBER FOR FIXING SAID RESPECTIVE CHARGE UNIT TO SAIDMEMBER, WITH SAID CHARGE UNIT SHOULDER BEARING ON SAID MEMBER ON THESIDE OPPOSITE SAID NUT.